detection of beet necrotic yellow vein virus (bnyvv) in some common weeds of sugar beet fields in fars province

rhizomania is one of the most important sugar beet diseases in iran and some other parts of the world. in this study, the infection rate of the most important weeds of sugar beet fields under natural condition  to the causal agent of the bnyvv (beet necrotic yellow vein virus) disease  was investigated at fars agricultural research center , iran. roots were collected from the infected weeds and bnyvv detection was carried out using elisa test. among the studied weeds, the highest rate of infection was detected in wild beet, beta vulgaris subsp. maritima and for the rest of weeds including amaranthus retroflexus, portulaca oleracea, chenopodium album, solanum nigrum, convolvulus arvensis, hibiscus trionum, and heliotropium europaeum no infection was detected. b. maritima seedlings were planted in infected soil in the greenhouse, and after two months, systemic leaf symptoms including mosaic, vein yellowing, short bunchy habit of growth (rosette), and severe stunting were observed. mechanical inoculation of bnyvv to b. maritima plants resulted in the emergence of disease symptoms. upon the inoculation of infected b. maritima leaves on  the three susceptible sugar beet cultivars (ic, pp8, and 7233 cultivars), yellow local and necrotic lesions were observed. the virus concentration in b. maritima was higher than the three aforementioned cultivars. this is for the first time to detect bnyvv in b. maritima and report it as a systemic host for bnyvv in iran. compared with other weeds grown in areas infected to rhizomania, this population of b. maritima (accession number 8901) had higher inoculums increment ability in the soil.